Venom injection by rattlesnakes (Crotalus atrox): peripheral resistance and the pressure-balance hypothesis

2003 ◽  
Vol 81 (2) ◽  
pp. 313-320 ◽  
Author(s):  
Bruce A Young ◽  
Molly Phelan ◽  
Malinda Morain ◽  
Melissa Ommundsen ◽  
Robert Kurt
Keyword(s):  
High Speed ◽  
Peripheral Resistance ◽  
Venom Gland ◽  
Pressure Balance ◽  
Crotalus Atrox ◽  
Digital Videos ◽  
Balance Hypothesis ◽  
External Forces ◽  
The Right ◽  
Different Levels

Differential venom injection by snakes, between two size classes of prey for example, has typically been explained within the rubric of the venom-metering hypothesis, which claims that snakes decide how much venom to inject in a given strike. Recently, an alternative, the pressure-balance hypothesis, was advanced, which attributes differential venom flow to the balance of internal forces acting at the venom gland and venom chambers and external forces acting at the exit orifice of the fang. This study tests these competing hypotheses. High-speed digital videos of predatory and defensive strikes by western diamondback rattlesnakes, Crotalus atrox, revealed considerable variation in the trajectory of the fang relative to the target, which would yield wounds with potentially different levels of peripheral resistance. The importance of peripheral resistance was also suggested by the expulsion of venom from the fang after withdrawal from the target (in 7% of strikes) and by the forceful ejection of fluid from the target around the embedded fang (in 2.8% of strikes). Experimental milking chambers were constructed that exposed the right and left venom-delivery systems to different levels of peripheral resistance; with increased peripheral resistance significantly less venom was injected into the chamber and significantly more venom was released on the chamber's surface.

Influence of social media marketing towards purchase of residential property

2019 ◽  
Vol 118 (6) ◽  
pp. 145-149
Author(s):  
A. Ekanthalingam ◽  
Dr. A. Gopinath
Keyword(s):  
Social Media ◽  
High Speed ◽  
Word Of Mouth ◽  
Marketing Strategies ◽  
Social Media Marketing ◽  
Purchase Decision ◽  
Residential Property ◽  
Customer Delight ◽  
The Right ◽  
Potential Customers

‘Marketing’ is not just an activity. It is a process, a philosophy and a phenomenon. The evolution of marketing has produced tremendous benefits to business and end consumers. The innovation in this field has been steady and yet at high speed. From ‘word of mouth advertising’ which was the only option earlier we are now at the mercy of what consumers are sharing about their experience on the internet. Social Media has become more powerful than what we think and this article shows how we can leverage this to benefit the top-line and customer delight. We dive deep to understand the influence Social Media can create towards purchase of residential property. As much complex it is to make the purchase decision of a property, it is equally difficult for marketers to send the right message to their target audience. Through this article, we are trying to see how marketers have transformed their traditional marketing strategies to address the needs of the millennial population, who are the most potential customers for property purchase.

scholarly journals Subsidising urban and sub-urban transport – distributional impacts

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Nils Fearnley ◽  
Jørgen Aarhaug
Keyword(s):  
Public Transport ◽  
High Speed ◽  
High Income ◽  
Urban Transport ◽  
Lower Income ◽  
Distributional Effects ◽  
Income Groups ◽  
Economic Profile ◽  
Different Levels ◽  
Distributional Impacts

Abstract Background and methods This paper studies distributional effects of public transport (PT) subsidies focusing on the Greater Oslo region. We identify how different PT markets enjoy different levels of subsidies. We describe how subsidies are distributed along PT modes and their respective patronage. This is done by document studies and travel surveys, supplemented by expert inquiries. Results We find that high-income groups, served by regional trains and high-speed crafts, receive large per passenger and per passenger-kilometre subsidy, while lower-income areas, typically served by local and regional buses, metros and local trains, receive lower subsidies per passenger. Peak traffic receives higher subsidies than off-peak traffic. The overall distributional profile is, however, found to be moderately progressive, in particular because of the socio-economic profile of the average PT passenger relative to the population as a whole.

Hard Nano-Crystalline Coatings for Cutting Tools

2007 ◽  
Vol 567-568 ◽  
pp. 185-188 ◽  
Author(s):  
Miroslav Piska
Keyword(s):  
High Speed ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Dry Cutting ◽  
Nano Crystalline ◽  
The Right ◽  
Machining Productivity ◽  
Hard Cutting ◽  
Cutting Tool Materials

Modern trends in metal cutting, high speed/feed machining, dry cutting and hard cutting set more demanding characteristics for cutting tool materials. The exposed parts of the cutting edges must be protected against the severe loading conditions and wear. The most significant coatings methods for cutting tools are PVD and CVD/MTCVD today. The choice of the right substrate or the right protective coating in the specific machining operation can have serious impact on machining productivity and economy. In many cases the deposition of the cutting tool with a hard coating increases considerably its cutting performance and tool life. The coating protects the tool against abrasion, adhesion, diffusion, formation of comb cracks and other wear phenomena.

Venom flow in rattlesnakes: mechanics and metering

2001 ◽  
Vol 204 (24) ◽  
pp. 4345-4351
Author(s):  
Bruce A. Young ◽  
Krista Zahn
Keyword(s):  
Functional Morphology ◽  
Delivery System ◽  
Flow Rate ◽  
High Speed ◽  
Distal Portion ◽  
Retrograde Flow ◽  
Crotalus Atrox ◽  
Direct Recording ◽  
Significant Difference ◽  
Digital Videography

SUMMARY The functional morphology of venom injection in Crotalus atrox was explored using high-speed digital videography combined with direct recording of venom flow using perivascular flow probes. Although venom flow was variable, in most strikes the onset of venom flow was coincidental with fang penetration, and retrograde flow (venom suction) was observed prior to fang withdrawal. The duration of venom flow was consistently less than the duration of fang penetration. The occurrence of retrograde flow, ‘dry bites’ (which accounted for 35 % of the strikes) and unilateral strikes all support a hypothesis for venom pooling in the distal portion of the venom-delivery system. No significant difference in temporal or volumetric aspects of venom flow were found between defensive strikes directed at small and large rodents. With the species and size of target held constant, the duration of venom flow, maximum venom flow rate and total venom volume were all significantly lower in predatory than in defensive strikes.

Simulation of Multi-Stage Compressor at Off-Design Conditions

2017 ◽  
Author(s):  
Feng Wang ◽  
Mauro Carnevale ◽  
Luca di Mare ◽  
Simon Gallimore
Keyword(s):  
Mass Flow ◽  
High Speed ◽  
Eddy Viscosity ◽  
Turbulence Models ◽  
Viscosity Model ◽  
Eddy Viscosity Model ◽  
Multi Stage ◽  
Pressure Profiles ◽  
Non Linear ◽  
The Right

Computational Fluid Dynamics (CFD) has been widely used for compressor design, yet the prediction of performance and stage matching for multi-stage, high-speed machines remain challenging. This paper presents the authors’ effort to improve the reliability of CFD in multistage compressor simulations. The endwall features (e.g. blade fillet and shape of the platform edge) are meshed with minimal approximations. Turbulence models with linear and non-linear eddy viscosity models are assessed. The non-linear eddy viscosity model predicts a higher production of turbulent kinetic energy in the passages, especially close to the endwall region. This results in a more accurate prediction of the choked mass flow and the shape of total pressure profiles close to the hub. The non-linear viscosity model generally shows an improvement on its linear counterparts based on the comparisons with the rig data. For geometrical details, truncated fillet leads to thicker boundary layer on the fillet and reduced mass flow and efficiency. Shroud cavities are found to be essential to predict the right blockage and the flow details close to the hub. At the part speed the computations without the shroud cavities fail to predict the major flow features in the passage and this leads to inaccurate predictions of massflow and shapes of the compressor characteristic. The paper demonstrates that an accurate representation of the endwall geometry and an effective turbulence model, together with a good quality and sufficiently refined grid result in a credible prediction of compressor matching and performance with steady state mixing planes.

scholarly journals Dynamic analysis of a ten-link tooth-lever differential transmission

2021 ◽  
Vol 939 (1) ◽  
pp. 012024
Author(s):  
A Abdukarimov ◽  
I Saidakulov
Keyword(s):  
High Speed ◽  
Reaction Force ◽  
Transmission Mechanism ◽  
Force Analysis ◽  
Axis Of Rotation ◽  
Processed Material ◽  
Differential Transmission ◽  
External Forces ◽  
Force Calculation ◽  
Force Characteristics

Abstract This article discusses the dynamics of a ten-link tooth-lever differential transmission mechanism. The force analysis of the transmission mechanism is given in order to find the dependence for determining the reaction in kinematic pairs and the balancing moment of the pair of forces and to show some features of the tooth-lever transmission mechanism. The force calculation was carried out taking into account the accelerated movement of links since their acceleration in modern high-speed machines is very significant. To obtain a more accurate concept of the external forces and moments loading the transmission mechanism in the accelerated movement of the links, the dynamics of the transient process of roller technological machines was considered. Cases of feeding the processed material were considered both from the side of the intermediate gears and from the side opposite to the parasitic gears. Dependencies were obtained to determine the force characteristics of this mechanism. Cases of pressure unloading and overloading on the processed material from the side of the free shaft, depending on the location of the transmission mechanism are shown. The dependence of the reaction force of intermediate gears on their own axes of rotation on the angle between the levers is shown. With an increase in the angle between the levers, the reaction of the intermediate gears on the axis of rotation increases.

scholarly journals CONDITIONS FOR FORMING THE TEACHER'S DIGITAL COMPETENCY IN THE POSTGRADUATE EDUCATION

2019 ◽  
Author(s):  
Iryna Vorotnykova
Keyword(s):  
Professional Development ◽  
High Speed ◽  
Postgraduate Education ◽  
International Standards ◽  
National Standards ◽  
It Infrastructure ◽  
Digital Competence ◽  
Postgraduate Students ◽  
Digital Competency ◽  
The Right

The article defines the conditions for the formation of a teacher's digital competence in postgraduate education. The analysis of the international standards of UNESCO, the European digital competence framework for citizens (DigComp 2.1 and educators (Digcompedu), and the generalization of the criteria for the definition and assessment of digital competence among teachers. The results of the study are based on the experience of improving the skills of teachers of the city of Kyiv using empirical methods: observation, survey (questionnaires, interviews). The questionnaire allowed to identify the main inquiries of teachers regarding the formation of individual trajectories of professional development, including in The conditions of the formation of the digital competence of teachers in the system of postgraduate pedagogical education are determined: the digitalization of education, the availability of legal documents on standards and requirements for the teacher's digital competency (international, institutional, national), the need to develop and implement the criteria for the development of digital competency teachers (tests, questionnaires, etc.), introduction of international, domestic projects on the use of ICT, readiness of postgraduate students Go to ensure the formation of the digital competency of teachers (IT infrastructure, availability of scientific, educational and environmental resources), IT infrastructure of the educational institutions in which the teacher works (hardware, software, including digital laboratories, connection to high-speed Internet, personalized informational and educational environments, etc.). In addition, an important condition is determined by the teacher's motivation to continuous professional development and self-assessment of his digital competence. It is proved that the development and implementation of national standards for teacher's digital competence, giving him the right to decide for themselves in which institutions to improve their qualifications, promote the introduction of new approaches to constructing individual paths for developing digital competency of teachers.

I.—On Didymograptus, Tetragraptus, and Phyllograptus

1895 ◽  
Vol 2 (11) ◽  
pp. 481-492
Author(s):  
Gerhard Holm
Keyword(s):  
Proximal Part ◽  
The Right ◽  
True Structure ◽  
Different Levels

As has been previously indicated (see p. 439), the conclusion might be drawn from Moberg's description and figures of this species, interpreted by the knowledge of the true structure of the Didymograptus polypary, that the structure of the proximal part could in no essential particulars be separated from that just described in D. minutus, Mut. Consequently the genus Isograptus, which was proposed by Moberg for the species in question, is not authorized—at least, as founded on any of the characters cited by Moberg. The differences between Isograptus and Didymograptus, to which latter genus the species is referred by Nicholson, ought to be, according to Moberg, that in Didymograptus “both stipes arise at somewhat different levels on the sicula,” and that “each branch is itself bilaterally symmetrical”; whilst, on the contrary, in Isograptus the stipes should “arise bilaterally symmetrical from the sicula,” and each branch is not itself bilaterally symmetrical. As we have seen above, in reality in Didymograptus the left stipe is not bilaterally symmetrical, and the symmetry in the right stipe is entirely the same as that which is described by Moberg in Isograptus, namely, obliquely near the base, because the stipes do not arise from the side of the sicula, but from the “connecting” canal.

Knowledge Worker Profile

2012 ◽  
pp. 102-118
Author(s):  
Gulgun Kayakutlu
Keyword(s):  
Human Resource ◽  
Economic Crisis ◽  
Performance Measures ◽  
Value Creation ◽  
Knowledge Worker ◽  
Skill Requirements ◽  
New Vision ◽  
The Right ◽  
Different Levels

One of the major reasons for economic crisis of 2008-2009 is determined as value delivery. Major resource of value creation is the knowledge worker who works at different levels of an organisation. This study analyses knowledge worker studies in diverse disciplines, in order to determine the requests. The goal of the study is to propose a framework to clarify the skill requirements by integrating the requests at operational, team, organisational and inter-organisational levels with drivers provided by educating, attracting, motivating and retaining strategies. The framework facilitates employing the right employee for the right post while balancing the requests and the performance measures. This new vision will be beneficial for managers, human resource experts, and educators.

Business Intelligence Maturity Framework

2019 ◽  
pp. 44-63
Author(s):  
Chee-Sok Tan ◽  
Wai-Khuen Cheng ◽  
Jie Ren ◽  
Siew Fan Wong
Keyword(s):  
Business Intelligence ◽  
Delphi Study ◽  
Qualitative Approach ◽  
Implementation Success ◽  
Two Stage ◽  
Scarce Resources ◽  
Critical Areas ◽  
Enterprise Level ◽  
The Right ◽  
Different Levels

This chapter builds an enterprise-level business intelligence maturity (EBIM) model that facilitates an improved view of the path in business intelligence (BI) implementation. The authors adopted a two-stage qualitative approach, namely a Delphi study followed by case studies. The findings reveal that a comprehensive EBIM model enables organizations to plan, assess, and manage their BI initiatives more effectively than previously. In addition, this study lists important key process areas (KPAs) that influence BI implementation success. The authors found that the KPAs in different levels and dimensions help organizations identify critical areas in need of maximum attention and channel their scarce resources to improve those areas. Further, the entire EBIM framework fosters better use of limited resources in critical areas, which is likely to have a greater effect at the right time.

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